Treatment of fatty oils



Oct. 30, 1951 R. J. TAYLOR TREATMENT OF FATTY OILS Filed Nov. 18, 1948PERIOD OF ACTIVATION (HOURS) INVENTOR. REGINALD JAMES TAYLOR BY HISATTORNEYS Patented Oct. 30, 1951 TREATMENT OF FATTY OILS Reginald JamesTaylor, Wirral, England, ass'lgnor to Lever Brothers Company, Cambridge,Mass., a corporation of Maine Application November 18, 1948, Serial No.60,703 In Great Britain November 19, 1947 9 Claims. (Cl. 260-428) areused for the vitaminization of foodstuflsf such as margarine and forthis purpose it is desirable that the oil should possess noobjectionable flavors.

' Certain processes for removing objectionable flavors from oils arealready well known. "Some of these processes only remove part of thecompounds which give the objectionable flavors. Moreover, in certain ofthese processes new substances giving objectionable flavors may beformed. Other processes, when applied to oils containing vitamin A, havethe disadvantage of resulting in undesirable losses of the vitamin or anundesirable change in the vitamin. In certain processes the vitamin Aesters are completely converted into the vitamin A alcohol, which ismore unstable.

The chromatographich treatment of" vitamin containing oils has also beenproposed for various purposes, but no practicable process for removingobjectionable flavors from such oils .is believed to have been devisedso far.

It is an object of the present invention to pro vide a process for thecomplete removal of objectionable flavors from vitamin A containing oilswhich is simple in operation and by means of which satisfactory yieldsof recovered vitamin may be obtained.

Another object of the invention is to provide a method forsimultaneously removing completely the objectionable flavors fromvitamin A containing oils and increasing the concentration of vitamin Atherein.

The present invention uses a chromatographic method and employs for thispurpose a column of activated alumina to be defined and described inmore detail hereinafter through which-I the oil, in solution in anon-polar saturated hydrocarbon or a mixture of such hydrocarbons ispassed. It has been found that all the undesirable and objectionableflavors are retained on the alumina, while the resulting bland-tastingoil comprising the major portion of the original. oil and containingmost of the vitamin A in 2 chemically unaltered form passes through.

For chromatographic processes various forms of activated alumina areknown, as well as various methods of preparing thematerial. For thetreatment of materials containing relatively uristable compounds such asvitamin A, a highly active material is undesirable as, apart from otherconsiderations, it tends to bring about destruction of the vitamin, andto introduce other undesirable changes in the oil. The various methodsproposed for de-activating highly active aluminas, for example byexposure to a humid atmosphere or by the addition of water, have thedisadvantage that the degree of deactivation is difiicult to control,and the alumina, after use, can be reactivated only by difliculttreatment and cannot readily be brought back to the original activity ina simple manner.

Alumina is known to exist in a number of distinct 'forms. One of theseis the gamma form, which has already been described in the literature,for example in the article by Blitz et al., Zeitschrift fiiranorganische Chemie, volume 186, page 373. It has been found that byusing a column of crystalline gamma anhydrous alumina in thechromatographic treatment of oils containing vitamin A in solution in anonpolar hydrocarbon solvent, the fishy and other undesirable flavorsmay be removed while the oil, containing the vitamins in solution,passes through the column.

Such an alumina may be prepared by heating a crystalline gamma aluminatri-hydrate to a temperature and for a length of time suflicient todrive 01f the combined water, but insuflicient to convert the materialto the inert crystalline alpha form. The complete change from thetri-hydrate to the gamma anhydrous state takes place above 500 C. Theactivity of the material, although exhibiting the same immediate andabrupt change, does not remain static with continued heating, butdecreases, and the rate of decrease and the limiting value which isobtained depend upon the temperature.

In the accompanying drawing there are shown curves giving the relationbetween time of activation and activity at various temperatures.

The activity of the alumina may be measured by its-absorptive capacityfor a dye. One method for making such measurements is as follows:

A solution of waxoline blue in dry, freshly distilled petrol ether isprepared and its optical density at 650 mu for a 1 cm. depth of solutionis adjusted to 2.00 just prior to the test. 0.2 g. of freshly heatedalumina is added to 50 c. c. of dye solution in a c. c. stoppered flask,dispersed well and allowed to stand for 5 minutes. The dye solution isthen decanted and. the alumina washed with 2 lots of 5 c. c. petroleumether. The adsorbed dye is removed with successive lots (4 c. c. 4 c. c.2 c. c.) of absolute alcohol and filtered through a small sintered glasscrucible. The filtrate is transferred to a 10 c. c. graduated flask,adjusted to this volume and the strength of solution determined. Fromthis the weight of dye in milligrams adsorbed by 1 g. of alumina iscalculated, and this is used as a measure of the activity.

ured as described in the preceding paragraph, is

suitable. The material should be substantially free from adsorbed water,in distinction to the wa e e i9; P -1;-

material deactivated by viously.

According to the present invention therefore,

to the weight of oil treated before the alumina is .revivified ,hasaconsiderable effect upon the ref'sults obtained. When the ratio is'low, 1. e., of

the order of less than 1:1, the removal of objectionable flavorsgenerally tends to be incomplete but the recovery of vitamin A tends toapproach 100%. When the ratio is somewhat higher, 1. e.,

there is provided a process fpr the treatment of 7 oils containingvitamin A (as "hereinbeiore fd fined) which comprises passing the "oil"insolution in a non-polar saturated hydrocarbontormixture of suchhydrocarbons, through a column of anhydrous activated gamma alumina.free from adsorbed water, whereby objectionablelfla'vors are removedfrom the oil, and separating the resulting bland-tasting oil ,from thesolvent. Preferably the column of alumina is washed with furtherquantities .of solvent until as (much as possible of the oil and vitaminare recovered without the objectionable flavored substances held on thecolumn also being washed out.

The use of the above describedform of alumina is particularlyadvantageous when the process for the treatment of the oils is carriedouton va large scale. Owing" to the fact that the alumina reaches asteady state of activity on heating, this statefmay be arrived at againby heating to the same temperature. "Thisifact is made'use of toeconomicadvantage in the large scale applicag tion of theinvention. Acolumn of lumina; after being used to treat the oil, mayfb'erevivified"first by Washing with a hydrocarbonsolventcontaim ing say"10.% alcohol.This alcohol displaces the adsorbed substances of 'the alumina. The 'col,umn is then heated (for example by .means of steam which is passedthrough a surrounding jacket) ,fand the alcoholis driven ofi bypassing 7Warm air through the column. Whenall the alcohol .is removed/the columnis ready {for the treatment of a further batch "of oil. After a numberofsuch treatments thema'teria'lis found toibecom'e less efficient andthe alumina is re' moved. It can "then 'be reactivated simply by heating.to the same temperature to which it was originally activated, whereuponit is ready er a further cycle of treatment, being revivifled as described above after each treatment. Any non-polar saturated liquidhydrocarbon or mixture of such hydrocarbons maybe usedlas solvent fordissolving the oil treatment in ac-, cordance with the presentinvention. In-the examples that follow petroleum-ether v(13.1 40 to 60C.) is-described as a solvent, but other nonpolar hydrocarbon solventssuchas benzine (B. P. 75-95 .C.) or cyclohexane may be used.

While it is to be understood that the invention is not to be limited byany theory advanced here in, it is believed that the non-polarity of thesolvent, or the lesser polarity thereof as com The ratio of weight ofalumina is the column;-

of the order of 22.1 or 3:1, the removal of objecitionable l flavors issubstantially complete and t'he concentration of the vitamin in therecovered oil is about the same as in the initial oil. When "ther'atio"ishighj-ive of the order of 10:1 or '-20:1-or higher, the removal ofthe objectionable flavors is complete and the concentration of vitaminin the recovered oil is raised remarkably withisurprisingly little lossofvitamin, ,sinceit is found that the alumina retains .a portion of theoil while the vitamin passes through with .the .u nadsorbed oil. p

When the method is carried out primarily for theipurpose of removing theobjectionable flavors without increasing "the concentration ofthevitamin,.,the.ratio of Weight of alumina in the column to the weightofoil treated in a given run is thereforejp'referably maintained atabout.3.:1, although lower ratios as low as about 1:1. may be used. 1 '1When the methodis carried out primarilyLfor the purpose of increasingthe concentration of the" vitamin in the oil, and incidentally toachieve complete removal of. the objectionable flavors, the ratio 'ofweight of alumina in the column to the weight of oil treatedin'a'given'runis prefer-i ably maintainedatlabove 3 :1.

The following examples are illustrative of the several ways in which thepresent inventionmay bepracticed. p f r e i 5 0 -g-rams of a'sodareflned shark il-iver:oil-containing 100,000 I. U. per gram of vitamin Aester were-madeintoa 25 %.-weight/-volume (grams/cc.)

solution in-petroleum ether (HP. 40 Cj.-r60 Cf.)

Thissolution -waspassed through a column have .ingan internal-diameterof 1 (internal diameter) and containing ;-grams'of alumina in anactivated anhydrous gamma 4 form. The column was washed with 300 cc.of-the same-petroleum ether and thefinal washings were almost completelyfree from oil. .The recovered oil, after removal :of the solvent, wasfree from objectionable flavors. 47.6 grams of oil were recovered havinga'potency of 100,000 I. .U. per gram, corresponding to a recovery of95.2% 'of the vitamin A. V

Example 2 21 grams of a crude dogfish liver .011 containing 17,000 I..U. per gram of vitamin A ester were madeinto a 25% weight/volumesolution in ben-. zine ..(B.- P. 75 C.,-9.5 ..C.);. .Thissolutionwaspassefdthroug'h. a. column having an internal di-. ameter of one inchand containing 63 grams of aluminaflas described in Example 1. .Thecolumn was washedwith I57 cc..of ireshbenzine. v20.1

'gramsof oil were recovered and were free from objectionable flavors.,.The potency of the recovered oil was 16,5001. U. per gram,corresponding to a recovery of: 92.6 of the vitamin :A.

Example .3

50 grams .ofa soda-refined whale liver .o ilhaving a vitaminA potencyof.12,600 I. Urper gram, of which;ab out'70% was in .theQform of thealcol hol, were made .into .a..25% weight/volume solution petroleum .ether(B. P. 40.jC.-.60 ..C.').. Thissolution was passedthrough a columnhavleling an internal diameter of 1%" and containing 150 grams of alumina asdescribed in Example 1. The column was washed with 350 cc. of petroleumether. 48.6 grams of oil, free from objectionable flavors, wererecovered. The potency of the recovered oil was 11,700 I. U. per gram,corresponding to a recovery of 90.1% of the vitamin A.

Example 4 50 grams of a soda-refined palm oil containing 474 microgramsof carotene per gram were made into a 25% weight/volume solution inbenzine (B. P. 75 C.-'-95 C'.). The solution was passed through a columnhaving an internal diameter of one inch and containing 100 grams ofalumina as described in Example 1. The column was washed with 350 cc. offresh benzine. 46.5 grams of oil, free from objectionable flavors, wererecovered. The recovered oil contained 454 micrograms of carotene pergram, corresponding to a recovery of 89.7%.

Example 5 50 grams of a soda-refined shark liver oil containing 99,000I. U. per gram of vitamin A ester were made into a 25% weight/volumesolution in petroleum ether (B. P. 40 C.-60 C.) This solution was passedthrough a column having an internal diameter of 1%" and containing 150grams of alumina in an activated crystalline anhydrous form. The columnwas washed with further quantities of petroleum ether until the washingswere almost completely free from oil (about 350 00.). 44.6 grams of oilwere recovered. After removal of the solvent, the recovered oil had apotency of 98,500 I. U. per gram, corresponding to a recovery of 88.9%of vitamin A.

Example 6 35 grams of a crude dogfish liver oil having a vitamin Apotency of 1600 I. U. per gram were made into a 25% weight/volumesolution in petroleum ether (B. P. 4060 C.). This solution was passedthrough a column having an internal diameter of 1%" and containing 400grams of alumina as described in Example 1. The column was washed with1400' cc. of petroleum ether. 4.47 grams of oil, free from objectionableflavors, were recovered. The potency of the recovered oil was 8800 I. U.per gram, corresponding to a recovery of 82.0% of the vitamin A.

Example 7 10 grams of a crude liver oil having a vitamin A potency of160,000 I. U. per gram were made into weight/volume solution inpetroleum ether (B. P. 40-60 C.). This solution was passed through acolumn having an internal diameter of 1 and containing 200 grams ofalumina as described in Example 1. The column was washed with 600 cc. ofpetroleum ether. 1.35 grams of oil, free from objectionable flavors,were recovered. The potency of the recovered oil was 1,056,000 I. U. pergram, corresponding to a recovery of 89% of the vitamin A.

It should be understood that the above description and examples aremerely illustrative of the invention and that any changes obvious tothose skilled in the art may be made without departing from the scope ofthe invention as defined by the following claims.

I claim:

1. A process for removing undesirable flavorlmparting materials from anoil containing vitamin A without reducing appreciably the vitamin Acontent of the oil which comprises dissolving said oil in a non-polarsaturated hydrocarbon solvent and passing the resultant solution throughanhydrous gamma alumina.

2. A process as defined in claim 1 wherein the anhydrous gamma aluminais formed by heating crystalline gamma alumina trihydrate to atemperature above 500 C. for a length of time sulficient to drive offthe combined water but insufficient to convert the material to the inertcrystalline alpha form and wherein the anhydrous gamma alumina has auniform adsorptive capacity for waxoline blue dye of between 4.5 and 7.0mgm. per gram of alumina.

3. A process as defined in claim 1 wherein the ratio of weight ofalumina to the weight of treated oil is of the order of about 1:1 toabout 3:1 to substantially remove the flavor-imparting material fromsaid oil, but insufficient to increase the concentration of vitamin inthe oil.

4. A process as defined in claim 1 wherein the ratio of weight ofalumina to the weight of treated oil is at least 1:1.

5. A process as defined in claim 1 wherein the ratio of weight ofalumina to the weight of treated oil is of the order of about 10:1 toabout 20:1 to increase the concentration of the vitamin in the oil.

6. A process as defined in claim 1 wherein the concentration of oil inthe hydrocarbon solution is within the range of 10 to 40 parts by weightof oil in parts by volume of solution.

7. A method which comprises alternately passing a solution of vitaminA-containing oil in a non-polar saturated hydrocarbon solvent through acolumn of anhydrous gamma alumina and revivifying the alumina in situ bywashing the column with a mixture of non-polar saturated hydrocarbonsolvent and alcohol and heating the alumina until the alcohol is removedtherefrom.

8. A method which comprises alternately passing a solution of a vitaminA-containing oil in a non-polar saturated hydrocarbon solvent through acolumn of anhydrous gamma alumina and reactivating the alumina byheating it to a temperature above 500 C.

9. A process as defined in claim 1 wherein the non-polar saturatedhydrocarbon solvent is selected from the group consisting of petroleumether, benzine and cyclohexane.

REGINALD JAMES TAYLOR.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS vol. 186, pages 373 to 386 (February 1930).

Swain: Journal of Fisheries Reserach Board of Canada, vol. 6, August1943, pages 113 to 118.

1. A PROCESS FOR REMOVING UNDERSIRABLE FLAVORIMPARTING MATERIALS FROM ANOIL CONTAINING VITAMIN A WITHOUT REDUCING APPRECIABLE THE VITAMIN ACONTENT OF THE OIL WHICH COMPRISES DISSOLVING SAID OIL IN A NON-POLARSATURATED HYDROCARBON SOLVENT AND PASSING THE RESULTANT SOLUTION THROUGHANHYDROUS GAMMA ALUMINA.